Abstract: Deafness is the most prevalent sensory system impairment in human, about 70 % of genetic deafness belongs to nonsyndromic hearing impairment. It was estimated that the total number of genes involved in nonsyndromic hereditary deafness was over 100. So far, approximate 80 loci have been mapped to human chromosome, and 23 genes have been identified. In this paper, a family with nonsyndromic hearing impairment caused by intermarry was reported. There were 13 sufferers in two generations. Deduced from genetic analysis, neither autosomal dominant nor autosomal recessive inheritance was identified in this family, which suggested that hearing impairment in the family was probably caused by mitochondrial mutations.